The aluminum-titanium-boron ternary system is commonly used as grain refiners in aluminum melts in order to obtain a small, equiaxed grain size during solidification. This is important in order to increase the resistance to ingot cracking and in order to improve the mechanical properties and the surface quality of the aluminum alloys produced.
It is desirable, therefore, to produce such aluminum-titanium-boron alloys efficiently and with a minimum cost.
In addition, preparation of such alloys results in the formation of titanium diboride particles and clusters of said particles which are insoluble in the aluminum matrix. Although titanium diboride particles are desirable, it is desirable to minimize growth of the titanium diboride particles and clusters since they reduce the effectiveness of the alloy. Still further, preparation of such alloys results in the formation of TiAl.sub.3 particles and large titanium aluminide particles may cause processing problems.
In addition, currently KBF.sub.4 is commonly used as a commercial source of boron in obtaining these alloys; however, this material has a high cost which adds greatly to the raw material costs in producing these alloys.
U.S. Pat. No. 3,961,995 describes a process for producing certain aluminum-titanium-boron alloys including the formation of titanium diboride by reacting liquid aluminum with titanium oxide and boron oxide in solution in molten cryolite and quenching the alloy rapidly to cool and solubilize the reaction product. However, this reference is limited to boron contents of 0.2 to 0.8% and requires high operating temperatures generally in excess of 1000.degree. C.
Accordingly, it is a principal object of the present invention to provide an improved process for forming an aluminum base alloy containing titanium and boron.
It is a further object of the present invention to provide a process as aforesaid which is convenient and expeditious to perform and which is economical in commercial practice.
It is a still further object of the present invention to provide an improved aluminum-titanium-boron alloy.
Further objects and advantages of the present invention will appear hereinbelow.